Add a Manifest with, at end :
<compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
<application>
<!-- A list of the Windows versions that this application has been tested on and is
is designed to work with. Uncomment the appropriate elements and Windows will
automatically selected the most compatible environment. -->
<!-- Windows Vista -->
<!--<supportedOS Id="{e2011457-1546-43c5-a5fe-008deee3d3f0}" />-->
<!-- Windows 7 -->
<!--<supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}" />-->
<!-- Windows 8 -->
<supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}" />
<!-- Windows 8.1 -->
<supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}" />
<!-- Windows 10 -->
<maxversiontested Id="10.0.19041.0"/>
<supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}" />
</application>
</compatibility>
Add WS_EX_LAYERED to Edit control :
HWND hTextBox = CreateWindowEx(WS_EX_CLIENTEDGE | WS_EX_LAYERED, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | ES_AUTOHSCROLL | WS_BORDER, static_cast<int>(15), static_cast<int>(15), static_cast<int>(130), static_cast<int>(30), hwnd, (HMENU)50, (HINSTANCE)GetWindowLongPtr(hwnd, GWLP_HINSTANCE), NULL);
SetOpacity(hTextBox, 100);
with
void SetOpacity(HWND hWnd, int nOpacity)
{
SetLayeredWindowAttributes(hWnd, 0, (byte)(255 * nOpacity / 100), LWA_ALPHA);
}
Then it will appear :